It also says "community curated". The books are crowdsourced. Most contributors are clearly what you'd refer to as hackers, but there's nothing stopping you fro

It also says "community curated". The books are crowdsourced. Most contributors are clearly what you'd refer to as hackers, but there's nothing stopping you from posting a Philosophy book. I think it mostly points to the fact that (I'm willing to bet) most authors who'd willingly make their books available free of charge are of a technical bent. There are philosophy, economics, psychology books on the site. If you find any and you've got some time to spare, you're welcome to add to the site.